Magnetic time-delay mechanism



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Patented June 5, 1951 UNITED STATES PATENT OFFICE MAGNETIC TIME-DELAY MECHANISM Edmund O. Schweitzer, Jr., Northbrook, Ill.

Application February 16, 1948, Serial No. 8,679

17 Claims.

My invention relates, generally, to magnetic control mechanisms and it has particular relation to magnetic time delay mechanisms.

Among the objects of my invention are: To change the operating characteristics oi a magnetic circuit by flow of a material from one position to another as a function of the time required for the flow to take place; to employ nely divided magnetic particles as the material which flows from lone 4position to the other; to cause a permanent magnet to move from one position to an alternate position as a result of such flow of magnetic material; to change the reactanee of coil as a result of such flow of magnetic material; to employ an electrical conducting liouid as the material which flows from one position to the other; and to employ the electrical conducting liquid as a single turn secondary winding inductively coupled to said coil thecurrent carrying capacity of which winding is increased as a function o the time required for the flow to take place.

Other objects of my invention will, in part, be obvious and in part appear hereinafter.

My invention is disclosed in the embodiments thereof shown in the accompanying drawing and it comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the constructions hereinafter set forth and the scope of the application of which will be indicated in the appended claims.

For a more complete understanding of the nature and scope of my invention, reference can be had to the following detailed description, taken together with the accompanying drawing, in which:

Figure l illustrates, somewhat diagrammatically, a magnetic control mechanism embodying my invention;

Figure 2 is a view, partly in side elevation and partly in section and somewhat diagrammatic in character, illustrating another embodiment of my invention; and

Figure 3 is a View, similar to Figure 2, and showing still another embodiment of my invention.

Referring now particularly to Figure 1 of the drawing, it will be observed that the reference character II)l designates, generally, a time delay device constructed in accordance with one embodiment of my invention. The time delay device IIJ includes an hourglass housing II that is formed of non-magnetic material such as a suitable plastic, either transparent or opaque, or brass. The housing II has an upper portion or upper container section I2 and a lower portion or lower container section I3 which are interconnected through a restricted aperture or constriction I4. In this embodiment of the invention a body I5 of nely divided magnetic matesteel balls, is located within the housing II and is arranged to flow from one portion or section I2 to the other portion or section I3 under the inuence of gravity, The ends of the housing Il may be closed by suitable plugs I6 also of nonmagnetic material.

It will be understood that opposite ends of the housing I I may be symmetrical so that it may be turned upside down to provide the desired time delay by ow of the body I5 of nely divided magnetic material from one portionor section to the other as the case may be. However, the end portions of the housing I I may be unsymmetrical, if desired, where the time delay function is to be performed with the housing I I occupying one position only. For example, the upper portion I2 may be a long narrow cylinder or it may be a large diameter cylinder as compared to the size of the lower portion I3 where the time delay function is to be performed by the flow of the body I5 of nely divided magnetic material into the lower portion I3.

Movably mounted along the lower portion or lower container section I3 of the housing II is a permanent magnet I8 which may be carried at one end of an arm I9 that, in turn, is biased by a spiral spring 20 to move the permanent magnet I8 away from the housing II. As shown, the spiral spring 29 may be anchored to a suitable support 2|.

The movement of the arm I9 in response to movement of the magnet I8 on being attracted toward the housing I I when the body I5 of nely divided magnetic material has flowed into the lower portion or lower container section I3 may be employed to perform any desired control function. For example, the arm i9 may carry a pin 22 which serves to maintain closed separable contacts 23 that are connected in a circuit including a battery 24 and a lamp 25.

It will be understood that the contacts 23 are held closed normally by the biasing force applied to the arm EQ. Now when the lower portion or lower container section I3 of the housing II is filled by the body I5 of finely divided magnetic material, the permeability of the path of the flux from the magnet I@ within the housing II is increased. As a result the permanent magnet I 8 is attracted to the body I5 of finely divided magnetic material within the lower portion or lower container section i3 of the housing II against the biasing force exerted by the spiral spring 20 and contacts 23 are separated. The energizing circuit for the lamp 25 is opened thereby and it is extinguished. The extinguishment of the lamp 25 takes place at the end of a time interval the length of which is determined by the time required for the body I5 of finely divided magnetic material to flow through the restricted aperture `or constriction is into the lower portion or lower container section I 3 in an amount sufficient to cause the permanent magnet I8 to be attracted thereto as described. Obviously, the contacts 23 can be normally open contacts rather than normally closed contacts with a circuit being closed rather than -opened at the expiration of a predetermined time interval. Instead of separable contacts 23, a suitable mechanical device can be operated or tripped by the movement of the arm I9 in response to change in position of the permanent magnet I8 as will be understood readily.

When it is desired to shift the housing I I so as to cause the body I of nely divided magnetic material to flow from the lower portion or lower container section I3 back to the upper portion or upper container section I2, the housing II may be mounted to rotate about a horizontal axis that is transverse to its longitudinal axis. For this purpose the housing II may be secured to one end of a shaft 28 that is mounted for rotation by a support 29. Suitable friction means may be provided for holding the housing II in any position to which it may be rotated. The shaft 23 has a knurled handle 30 to facilitate gripping the same for rotating the housing II from one position to the other.

In Figure 2 of the drawing another embodiment of my time delay device is illustrated, generally, at 32. In this embodiment of my invention the housing I I may be identical with the housing II shown in Figure l and described liereinbefore` The time delay function likewise may be effected by the flow of the body I5 of nely divided magnetic material from the upper portion or upper container section I 2 through the restricted aperture or constriction i4 to the lower portion or lower container section I3.

In lieu of the permanent magnet i8, shown in Figure 1, a c-oil 33 surrounds the lower portion or lower container section I3 of the housing II. The coil 33 may be connected for energization to a source 34 of alternating current, such as a 60 cycle I I!) volt source. The source 34 is arranged to energize a load device 35 of any suitable character which, as shown, is connected in series circuit relation with the coil 33,

Before the body I5 of finely divided magnetic material begins to flow through the aperture I4 into the lower portion or lower container section I3 of the housing II as shown in Figure 2, the reactance of the coil 33 is relatively low and the current ilow to the load device 35 is correspondingly high. Now, as the body I5 of nely divided magnetic material lls the lower portion or lower container section I3, the reactance of the coil 33 is increased and there is a corresponding reduction in the iow of current therethrough and to the load device 35. It will be understood that the change in now of current through the load device 35 takes place as a function of the time required for the body I5 of iinely divided magnetic material to flow into the lower portion or container section I3.

It is desirable to provide a high permeability path for the return ilux of the coil 33 in order to reduce the flux concentration adjacent the restricted aperture or constriction I4. For this purpose a sleeve 36 of magnetic material may be located around the coil 33.

In Figure 3 of the drawing there is illustrated, generally, at 38 still another embodiment of my time delay device. It employs the same housing II as shown in Figure l and described heJeinben fore with certain slight modincations. Instead of employing the body I5 of finely divided magnetic material to provide the desired time delay function, an electrical conducting liquid 39, such as mercury, is employed. The liquid 39 is arranged, as will be understood readily, to ilow through the restricted aperture or constriction I4 from the upper portion or upper container section I2 to the lower portion or lower container section I3. In so doing the liquid 39 forms a single turn secondary winding around a core 40 of magnetic material which, as shown, is located within the lower poriton or lower container section I3 of the housing I I. The liquid 39 gradually iills the space between. the outside of the core 40 of magnetic material and the inner walls of the lower portion or lower container section I3. The conductivity of this single turn short circuited secondary winding is increased as the quantity of the liquid 39 increases. There is a corresponding reduction of the current owing through the coil 33 and the load device 35 since the reactance oi the coil 33 is increased as a function of the increase in current now throughithe liquid 39 surrounding the core 49. Thus, the current flowing through the load device 35 is decreased as a function of the flow of the liquid 39 into the space around the core 43.

Since other embodiments of my invention can be made without departing from the spirit and scope thereof, it is intended that all matter shown in the accompanying drawing and described hereinbefore shall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

l.. A magnetic control mechanism comprising. in combination, a pair of containers, a permanent magnetic circuit associated with one of said containers, and magnetic means arranged and adapted to now through a restricted orice solely under the influence of gravity to said one container from the other to vary the operating characteristics of said magnetic circuit as a function of the time required for such flow to take place.

2. A magnetic control mechanism comprising, in combination, a pair of containers, an electromagnetic circuit associated with one of said containers, and magnetic means arranged and adapted to iiow solely under the influence of gravity through a restricted orifice to said one container from the other to vary the operating characteristics of said magnetic circuit as a function of the time required or such now to take place.

3. A magnetic control mechanism comprising, in combination, a pair of containers, an electromagnetic circuit associated with one of said containers, means providing a low reluctance path around said electromagnetic circuit to limit the magnetic iiux generated thereby substantially within its connes, and magnetic means arranged and adapted to flow to said one container from the other to vary the operating characteristics of said magnetic circuit.

Il. A magnetic control mechanism comprising, in combination, a pair of containers, an electromagnetic circuit associated with one of said containers, and nommagnetic electrical conducting means arranged and adapted to now through a restricted orince to said one container from the other to Vary the operating characteristics of said magnetic circuit as a function of the time required. for such ow to take place.

5. A magnetic control mechanism comprising, in combination, a pair of containers, an electro magnetic circuit associated with one of said containers, a magnetic core in said one container, and liquid electrical conducting means arranged and adapted to flow through a restricted orifice to said one container from the other and around said core to increase the reactance of said electromagnetic circuit as a function of the time required for such flow to take place.

6. A time delay mechanism comprising, in combination, upper and lov/er containers, a magnetic circuit associated with said lower container, and means arranged and adapted to ilow through a restricted orifice from said upper container to said lower container solely under the iniiuence of gravity to vary the operating characteristics of said magnetic circuit as a function of the time required for the flow to take place.

7. A time delay mechanism comprising, in combination, upper and lower containers, a permanent magnetic circuit associated with said lower container, and magnetic means arranged and adapted to iiow solely under the influence of gravity through a restricted orice from said upper container to said lower container to vary the operating characteristics of said magnetic circuit as a function of the time required for the flow to take place.

8. A time delay mechanism comprising, in combination, upper and lower containers, an electromagnetic circuit associated with said lower container, and magnetic means arranged and adapted to flow from said upper container to said lower container to vary the operating characteristics of said magnetic circuit as a function of the time required for the now to take place.

9. A time delay mechanism comprising, in combination, upper and lower containers, an electromagnetic circuit associated wtih said lower container, means providing a low reluctance path around said electromagnetic circuit to limit the magnetic iiuX generated thereby substantially within its connes, and magnetic means arranged and adapted to flow to said lower container from said upper container to vary the operating characteristics of said magnetic circuit as a function of the time required for the ow to take place.

10. A time delay mechanism comprising, in combination, upper and lower containers, an electromagnetic circuit associated with said lower container, and non-magnetic electrical conducting means arranged and adapted to ilow from said upper container to said lower container to vary the operating characteristics of said. magnetic circuit as a function of the time required for the now to take place.

11. A time delay mechanism comprising, in combination, upper andA lower containers, an electromagnetic circuit associated with said lower container, a magnetic core in said lower container, and liquid electrical conducting means arranged and adapted to flow to said lower container from said upper container and around said core to increase the reactance of said electromagnetic circuit as a function of the time required for the flow to take place.

12. A time delay mechanism comprising, in combination, an hourglass housing of non-magnetic material located in an upright position, a magnetic circuit associated with the lower portion of said housing, and means arranged and adapted to flow from the upper portion of said housing to its lower portion under the influence of gravity to Vary the operating characteristics of said magnetic circuit as a function of the time required for it to now through the restricted orice between said upper and lower portions of said housing.

13. A time delay mechanism comprising, ln combination, an hourglass housing of non-mags I netic material, means mounting said housing for rotation about a horizontal axis that is transverse to the longitudinal axis of said housing, a permanent magnet movably mounted adjacent the portion of said housing that occupies the lowermost position, means biasing said permanent magnet away from said housing, and magnetic means within said housing arranged and adapted to flow from its upper portion to its lower portion to provide a low permeability path for the ilux of said permanent magnet whereupon the same is attracted thereto against the force of said biasing means a predetermined time after magnetic means starts to flow, and means responsive to the movement of said perinagnet from one position to the other.

le, The invention, as set forth in claim 13, wherein the means responsive to the movement of the permanent magnet is separable contact means.

15. A magnetic control system comprising, in combination, an hourglass housing of non-magnetic material located in an upright position, a coil surrounding the lower portion of said housing and adapted to be energized from an alternating current source through a load device, and magnetic means within said housing arranged and adapted to flow from its upper portion to said lower portion to increase the permeability of the flux path within said coil and thereby its reactance as a function of the time required for the flow to take place whereby the current now through said load device is reduced correspondingly.

16. The invention, as set forth in claim 15, wherein a tubular member of magnetic material surrounds the coil to provide a high permeability path for its return flux and reduce the magnetic ilux at the constriction between the upper and lower portions of the housing.

17. A magnetic control system comprising, in combination, an hourglass housing of non-magnetic material located in an upright position, a coil surrounding the lower vportion of said housing and adapted to be energized from an alternating current source through a load device, a core of magnetic material within said lower portion of said housing and spaced from its inner wall, and a body of electrically conducting liquid within said housing arranged and adapted to flow from its upper portion to the space around said core in said lower portion to provide a single turn short circuited secondary winding inductively coupled to said coil whose current carrying capacity is increased as a function of the time required for the flow to take place whereby the current flow through said load device is reduced correspondingly.

EDMUND O. SCHWEITZER, JR.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS FOREIGN PATENTS Country Date Great Britain Nov. 29, 1928 France Dec. 10, 1908 Number Number 

